Amino acids are essential for many functions within the body. These functions include regulating metabolic pathways and the synthesis of enzymes, hormones, and neurotransmitters. In the supplement industry, amino acid supplements fall into two basic categories. These categories are essential amino acids (EAAs) and branched-chain amino acids (BCAAs).

EAAs and BCAAs

First, an essential amino acid, or indispensable amino acid, cannot be synthesized by an organism. That being said, our diet supplies these essential amino acids. There are 9 essential amino acids humans cannot synthesize. These are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine.

Secondly, 3 of those 9 essential amino acids—leucine, isoleucine, and valine—are called the branched-chain amino acids (BCAAs). They are named for their branched chemical structure. BCAAs account for 35–40% of the dietary essential amino acids in body protein. Also, 14–18% of the total amino acids in muscle protein. Among all the BCAAs, leucine is arguably the most important. This is because it stimulates the signaling pathway for protein synthesis in skeletal muscle.

See: What Are BCAAs?

Lastly, BCAA supplementation has been shown to improve measures of physical performance. Including, lean body mass, muscle hypertrophy, and muscle strength. Research has shown BCAA supplementation improves energy, decreases muscle fatigue during exercise, improves recovery, and aids in preventing muscle soreness after intense and long-duration exercise.

When to Take BCAAs

The timing of protein intake appears to be the most important factor in achieving positive training adaptations. While many athletes have different preferences for when to take amino acids, evidence from numerous studies suggests that the best time to take BCAAs is directly before or after your workout.

The period immediately after exercise is considered the ideal time for most individuals. Research has shown that this timing is the best for triggering muscle synthesis, preventing muscle damage and stimulating recovery. Also, decreasing fatigue and suppressing symptoms of delayed onset muscle soreness. However, you may decide the best for you from the information given below.

Why Use a BCAAs Before a Workout

If there is an even pattern of protein intake throughout the day, there is less benefit from consuming BCAAs before the workout. The body can only absorb and utilize a finite amount of amino acids at a given time. However, if exercising in a fasted state or if you have not had a meal within the hours prior, consumption of BCAAs before a workout would provide substrate your body needs.

See: Do Amino Acids Break a Fast?

Research has shown consuming BCAAs before exercising in a fasted state helps increase fat oxidation, prevent fatigue, and prevent muscle damage. Also, data show that taking amino acids before a workout can decrease the symptoms of delayed onset muscle soreness as much as 20%. In short, research suggests that taking amino acids 30-60 minutes before a workout can significantly increase training benefits.

Why Use a BCAAs During a Workout

BCAAs are unique from other amino acids because they metabolize in the muscle instead of the liver. Therefore, they are available in the bloodstream soon after ingestion for energy during exercise. Research shows that BCAA consumption during exercise helps increase exercise capacity or time to exhaustion. Especially during depleted muscle glycogen (glucose stored in the muscle for energy). More specifically, BCAAs help to counter the effect of depleted glycogen stores and provide an increased ability to sustain prolonged exercise.

See: Reducing Fatigue with BCAA Supplementation

BCAAs Reduce Central Fatigue

Additionally, supplementing with BCAAs during exercise helps to prevent central fatigue. In simplified form, the central fatigue hypothesis works as follows. When you are active, your body releases fat to burn. This increases the amount of free tryptophan in your body. Tryptophan is the precursor to serotonin, a neurotransmitter that brings on feelings of whole-body fatigue, as opposed to localized muscle fatigue.

In the body, BCAAs compete with tryptophan because they share the same transporter at the blood-brain barrier. By supplementing with BCAAs during exercise, free BCAAs in the body is increased and can compete with tryptophan. Meaning, that less serotonin is produced, which reduces the amount of central fatigue you feel.

Why Use BCAAs After a Workout

During a workout, muscle breakdown and muscle synthesis systems are both activated. However, post-workout muscle breakdown exceeds muscle synthesis until you ingest the amino acid, leucine. Leucine activates mTOR, which stimulates protein synthesis and muscle tissue growth. By consuming BCAAs immediately after exercise, your body can initiate muscle repair and growth.

While BCAAs are present in food and protein supplements, they can sometimes take too long to process to achieve full benefits during or after a workout. In separate supplement form, BCAAs aren’t bound to other amino acids, like they are in whey protein for example. Meaning, they can be digested and absorbed more quickly, which makes them more available to impact protein synthesis.

Take BCAAs 30 Minutes After Exercise

Once an individual consumes a protein, anabolism increases for about 3 hours postprandial with a peak at about 45–90 minutes. Therefore, studies suggest the best time to supplement with BCAAs is within the first 30 minutes after exercise.

See: What Is Muscle Protein Synthesis?

How Many BCAAs Should I Take?

In adults, both at resting and post-exercise, approximately 20-30 grams of protein at one time is ideal to stimulate muscle protein synthesis. Also, 5 grams of BCAA is roughly equivalent to 30 grams of protein. Therefore, a BCAA supplement of 2.5 - 5 grams would be ideal.

When to take aminoVITAL BCAAs for best results


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